Illinois officials say state workers retired at rates five times higher than average last month, an attempt to lock in benefits before an overhaul of the state's underfunded pension system takes effect June 1.

The Springfield bureau of Lee Enterprises newspapers reports that about 1,100 government employees were on track to retire last month, compared with an average of about 200 retirements per month. Final totals weren't immediately available.

Lawmakers overhauled the state's pension system in December in an effort to save $145 billion, by cutting benefits and raising the retirement age. Lawsuits filed by government employee unions attempting to undo the measure are pending in Sangamon County Circuit Court. They argue that the changes violate the state constitution.

Gov. Pat Quinn and other defendants are scheduled to respond to the lawsuit on May 15.

Some workers hope that by retiring early, they'll be able to keep their current benefit levels.

Timothy Blair, executive director of the State Employees Retirement System, said there's no guarantee that's the case.

"The potential upside is there and there's not a lot of downside for someone who is close to retiring anyway," Blair said.

Thousands of state university employees also are retiring earlier than expected because of an error in the pension law. It bases a university employee's benefits on last year instead of this year. Lawmakers have said they will fix the mistake.

Union officials are not surprised by the early departure of state employees.

"We hope the legislation will be overturned to avoid the harm to employees who are having to make major life decisions," said Anders Lindall, a spokesman for the American Federation of State, County and Municipal Employees.

State Sen. Chapin Rose, a Mahomet Republican, said he can understand why workers want to retire early.

"There is a brain drain that is happening here," Rose said. "But I think people are thinking a bird in the hand is worth two in the bush."